Cave-measurement contests may not get the average Joe's adrenaline pumping. But for an international team of scientists who toiled deep underneath the mountains in Guanxi, China, in 2013, new figures obtained via laser mapping have confirmed that the Miao Room chamber—a gigantic cavern that's part of the Gebihe cave network—is the world's biggest. How excited are scientists who study this sort of thing? "To me this is like discovering that K2 is larger than Everest!" one of the Miao Room expedition's leaders says in an email to National Geographic.
The Miao Room's total volume of 380.7 million cubic feet is roughly 10% greater than that of the former heavyweight cave champion: Malaysia's Sarawak Chamber; Sarawak does still retain the title for most surface area at 1.66 million square feet. The Miao Room cave can only be accessed by an underground stream: "You either have to swim or use a small boat to get in the first couple of hundred of meters," caving expert Andy Eavis tells NPR. Eavis also explains the sheer size of a space whose almost 1,000-foot-high ceiling makes it as tall as the Eiffel Tower: "The only thing you see is the floor that you're standing on. Unless you have a particularly powerful light ... you don't see the walls, and you don't see the ceiling." The curious can take a tour of the 3D model of Miao Room at National Geographic. (Read about a Minnesota man's unusual hobby: collecting caves.)